Inkjet printing technology is a technology in which printing of image or character is realized by controlling print head's nozzles ejecting ink droplet on printing media. The inkjet printer mainly comprises of print head, ink cartridge and control system. Print head ejects ink droplet, ink cartridge stores ink and supplies print head with ink, and the control system stores data of image to be printed, controls print head nozzles' ejection and detects ink level in the ink cartridge. In prior art, some technical measures are taken not only to prevent the user from purchasing and using low cost unqualified inks which may cause equipment breakdowns, but also to guarantee developer's interests on ink sales. At present, intelligent cartridge is commonly used. Take Epson's ink cartridge for example. An intelligent chip is installed in the interior part of the ink cartridge, and such chip can store fixed data, such as name of the manufacturer, date of production, ink type, capacity and cartridge model etc, and operating data that can be resaved, such as date of the first installment and consumed ink in the ink cartridge etc. When data recorded in the chip reaches the pre-determined ink measuring value, printer indicates ink is exhausted and stops printing; under such circumstance, the ink cartridge cannot be refilled, and must be replaced by a new ink cartridge with a intelligent chip to print again. Because data updating of the intelligent chip in the ink cartridge is controlled by the printer, so printer manufacturer designs ink cartridge with intelligent chip that is compatible with the printer mode. In prior art, small capacity of ink cartridge with intelligent chip inside leads to frequent ink cartridge replacement, which is time and effort consuming; in actual use, when printer shows exhaustion of ink, often there is still some ink in the cartridge, which makes the ink remaining in ink cartridge to be discarded; to some extent, it leads to increase cost, waste of resources and not environmentally friendly.